RPX announced today that it has acquired sub-license rights to a portfolio from Droplets that consists of patents related to Web-based application delivery. The transaction, which closed in December, also includes option rights to grant sub-licenses to prospective RPX clients. The transaction shields RPX software, media content, e-commerce, software, and financial services clients from significant patent exposure. Since 2006, Droplets has filed patent infringement suits against more than 50 defendants, mainly Internet content providers, online trading and banking sites, and online retailers.